One of the best there ever was. Try imagining taking a shot at almost 1.5 miles. Even with a good scope you better know your windage and elevation and be able to calculate in your head quickly. He was the best there ever was and embodies what the Marine Corps is. White Feather is a legend and a hero.
Heres a couple good books about Carlos Hathcock:
Marine Sniper & Silent Warrior both by Charles Henderson,
Carlos Hathcock "White Feater" by Roy Chandler
One Shot, One Kill by Charles Sasser & Craig Roberts, this book is about Marine snipers as a whole but lots of info on Gunny Hathcock. There's a few others about Marine snipers in VN out there too.